The seas around the UK are full of the weird and the wonderful. Paul Naylor tells us about the master of disguise
MASTERS OF DISGUISE
Chameleons might be more famous for it, but cuttlefish are nature's true masters of colour control, able to match any seabed almost instantly. In aquaria, they have even made attempts at imitating chess boards! From the moment of hatching, young cuttlefish can display at least 13 types of body pattern, made up from more than 30 different components.
Cuttlefish can use jet propulsion for rapid escape. A jet-propelled departure is often accompanied by the release of a cloud of ink to confuse a pursuer. Cuttlefish ink was once used by artists and known as sepia. The Latin name of the common large cuttlefish in UK waters is Sepia officinalis.
LOVE & LET DIE
A male cuttlefish seeks out a female and then protects her aggressively from other males. He displays brilliant zebra stripes which act as both a courtship advertisement and a warning to competitors. Females breed only once and die soon after laying their eggs. Dyed with ink, the black eggs, known as "sea grapes", are attached to seaweed in clumps.
Cuttlefish cannot live in very deep water because the cuttle bone, their internal skeleton and buoyancy compensator, could implode under high pressure.
Cuttlefish are in the same animal group as whelks and scallops but, unlike their relatives, they have sophisticated brains. They are almost certainly more intelligent than fish and are probably on a par with rats.
As well as eight arms, cuttlefish have two longer tentacles that can shoot out to seize prey. A sharp beak located behind the arms has a venomous bite, though not toxic to humans. The combination of arms, tentacles, beak and speed can turn a crab into a meal in seconds.
Appeared in DIVER - August 1999